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KentuckyFC writes "Black holes form when a large star runs out of fuel and collapses under its own weight. Since there is no known force that can stop this collapse, astrophysicists have always assumed that it forms a singularity, a region of space that is infinitely dense. Now cosmologists think quantum gravity might prevent this complete collapse after all. They say that the same force that stops an electron spiraling into a nucleus might also cause the collapsing star to 'bounce' at scales of around 10^-14cm. They're calling this new state a 'Planck star' and say its lifetime would match that of the black hole itself as it evaporates. That raises the possibility that the shrinking event horizon would eventually meet the expanding Planck star, which emerges with a sudden blast of gamma rays. That radiation would allow any information trapped in the black hole to escape, solving the infamous information paradox. If they're right, these gamma rays may already have been detected by space-based telescopes meaning that the evidence is already there for any enterprising astronomer to tease apart."

Sort of yes. "...under the force of its own gravitational attraction" would be more precise, I think. Gravity is a force, and weight is the measure of the gravitational force on a particular item. But it's common to think of weight as the force of gravitational attraction itself, and it's shorter to type.

And yes, as it collapses and the distance from particle A to the center of mass of the rest of the star decreases, the force of gravitational attraction (weight) increases.

I don't get black hole evaporation. Suppose a proton/anti-proton pair gets created at the event horizon and the proton falls in. Hasn't the mass of the black hole increased by one proton? If the anti-proton falls in, it will meet another proton and annihilate it (assuming conditions within the black hole still allow this), but with no way for the energy to escape, isn't it the same as increasing by the mass of the anti-proton (which is the same as a proton)?

I propose we try the experiment with whomever is supporting this switch to Beta.

As I understand it, that's almost exactly it. The catch is that the universe is now 2 protons heavier than it was, and it can't keep them. "Normally" the proton and antiproton would recombine and annihilate and it would be gone, but now that they're separated that can't happen. So the black hole's mass gets debited 2 proton masses. So the final result is that the hole is down 1 proton mass and the rest of the universe is up 1 proton mass.

But how can the black hole's mass go down when particles are being added to it?

Because the mass of that particle, and the particle that escaped, came from the black hole. So there is a net loss of mass. But the probability of this happening is so low that an immense number of eons are needed to evaporate a black hole, and the time required goes up with the cube of the mass. A solar mass black hole may take approx 10^66 years to evaporate [wikipedia.org]. That is because its gravity sucks almost as hard as Slashdot Beta.

well, both the proton and antiproton have mass, but in a sense, they have a sum of zero energy (since they came out of nothing, they add up to nothing). So one of them gets to have negative energy, and it's the one the black hole ate (otherwise you have a negative-energy proton floating around, which gets weird). So it's adding negative energy to a positive mass and winding up with a smaller positive mass.

The wikipedia article on Hawking Radiation can probably explain it better than me; I'm about at the li

But how can the black hole's mass go down when particles are being added to it?

Pair of virtual particles is created on the event horizon of black hole. One particles falls into the black hole, other escapes it. Total energy of the virtual pair must be conserved. The particle that escapes the black hole has positive energy, so the other particle must have equal but negative energy. When negative energy is added to the blackhole, it loses some mass because energy = mass.

I don't get black hole evaporation. Suppose a proton/anti-proton pair gets created at the event horizon and the proton falls in. Hasn't the mass of the black hole increased by one proton? If the anti-proton falls in, it will meet another proton and annihilate it (assuming conditions within the black hole still allow this), but with no way for the energy to escape, isn't it the same as increasing by the mass of the anti-proton (which is the same as a proton)?

That's one interpretation of the effect. The part that you're missing is what those virtual pairs represent. Quantum mechanics allow for the violation of energy conservation laws, as long as the violation doesn't last long enough for it to measured (it doesn't matter if it's measured or not, it matters whether it happens during a time period in which it would be possible to measure it). Virtual particles pop in out of nothing, so suddenly you have extra energy in the universe. Then they annihilate and d

Let’s take your scenario: a proton/anti-proton pair of virtual particles pops into existence from the quantum vacuum near the event horizon and the anti-proton spirals into the black hole, meaning that the proton no longer has it’s antiparticle to annihilate against. (Clearly we’re talking about energy in terms of mass-energy terms here.)

OK, the original virtual-particle pair ‘borrowed’ energy from the vacuum; that debt must be paid back because the universe’s energy must

So decaying black holes might be another source of gamma ray bursts? Interesting hypothesis. I suppose this would permit a big old star to bounce between being a black hole and a neutron star, depending on the rate of incoming material.

So, do I have to point out the obvious that the/. beta is horribly user-hostile to keep this from getting modded -1 insightful?

Undoubtedly... but why sabatoge even the classic experience for everybody while it lasts with fuck beta posts in every single story?

Quite frankly, if they weren't frequently so lengthy... say, only one or two lines, with a link to a more detailed message embedded within, I wouldn't really care or mind them... but many of these anti-beta posts take up almost a full screen of real-estate in classic mode as they are getting modded up by supporters of the notion, and just plain get in the way of actually bei

OK, so I understand (vaguely) that this essentially means stuff goes in but doesn't come out.

But if this Planck star bursts forth from a black hole, is any 'information' in a meaningful sense coming back out? Or is the collection of random bits which we defined as 'information' coming back out just a bunch of meaningless noise?

It sounds more like "stuff comes back out, but will have been so mangled by the process that it isn't, strictly speaking, what we'd call 'information'".

I think information is used in it's most abstract sense. Any particle or wave signals that that approach the black hole get consumed. I.e. when we look at it, we see nothing because light is absorbed. I'm probably wrong, though, and someone who studies the topic might be more apt at providing an explanation. Personally, I wonder what this means in terms of the second law of thermodynamics. When a black hole consumes energy and releases a Planck star, do either events reduce the entropy of the system?

The 2nd law isn't violated as whatever falls into the black hole either becomes part of the singularity/Plank star, or is expelled during the transition via Hawking radiation. Your question on entropy doesn't make sense, as the cosmologists are postulating that the Plank star *is* the black hole.

A black hole represents the maximum possible entropy for a fuck beta of that radius. Unless the Plank star is much much larger, and still has relatively high fuck beta, there would be a reduction in entropy in the fuck beta. However, reductions in entropy can happen "locally" when enough energy is fed into the fuck beta, so if this happens because of a lot of incoming energy, it would makes sense - much like fuck beta.

Neither know shit, they just throw shit at the wall and hope something sticks when someone finally gets around to testing.For Dice, that testing will come when they force me to use the shitty new beta version of the site. Spoiler: I won't stick around.

Dice released their 4th quarter filing...and it does not cast Slashdot in a good light:

Slashdot Media was acquired to provide content and services that are important to technology professionals in their everyday work lives and to leverage that reach into the global technology community benefiting user engagement on the Dice.com site. The expected benefits have started to be realized at Dice.com. However, advertising revenue has declined over the past year and there is no improvement expected in the future financial performance of Slashdot Media's underlying advertising business. Therefore, $7.2 million of intangible assets and $6.3 million of goodwill related to Slashdot Media were reduced to zero.

Looks like running AdBlock on Slashdot and turning off ads may soon be the cause of their demise...

I haven't seen the quoted article but can very much believe the story.

Slashdot patrons are a very discerning kind of consumer, they're not going to put up with advertisers flogging bullshit.
This obviously makes it hard for the typical Ad-agency boy to figure out what will pay the bills.

Over many years of internet use I've acquired a blind eye for advertisements and am perfectly capable of ignoring them without the use of adblocks, the exception is Flash, it's generally uncalled for and usually in bad tas

Popular website gets known for its high, loyal, repeat traffic count, perhaps needs funding to maintain services due to increasing demand. Investors start to take notice - MBA marketing types equate loyal, repeat traffic with high Nielsen ratings of old media, convince big holding company to invest $$$ based on business plan for "leveraging" loyal, repeat traffic to site to sell other goods/services (MBA-speak: "monetization"). Doesn't work out, popular website not meeting projected

And say I think that most of the community thinks Slashdot Beta sucks.

You can't tell that, since the vast majority of beta rants are by ACs. It could be the work of simply a small group. OTOH, if the people actually used their nicknames when posting, it might be possible to tell how many users are displeased.

Anonymous tips may be useful for the police, but in just about every other instance, they are ignored because they can't be validated or followed up with. Likewise with AC rants here.

If they're right, these gamma rays may already have been detected by space-based telescopes meaning that the evidence is already there for any enterprising astronomer to tease apart.

.

I doubt they said that, and whether they did or not the data is not there for any enterprising astronomer to tease out.

Any black hole of any realistic mass (say, 2.5 Solar masses and up) will take much, much longer than the current duration of our universe to evaporate. So, maybe this will happen, maybe not, but it for sure ha

Well first, they clearly state that these ARE NOT blackholes, they just look like them from the outside.Secondly, there are lots of blackholes about that are of many different sizes, including microscopic ones.Thirdly, it doesn't need to entirely evaporate, it just needs to shrink to the point that the event horizon meets the star.Lastly they did, in fact, make that statement if you read the article.

Yes, I have now read the article, and they were indeed talking about small primordial black holes. The trouble with that is

- there is no evidence that any black hole with a mass less than 2 solar masses exists.- there is no mechanism to form small black holes except primordially- there is good evidence [arxiv.org] that smaller primordial black holes do not exist

I stand by my statement. There is no harm in pointing out the theoretical possibility, but in reality this is not going to be found burie

HI.
I posted this to see what it would look like on the beta website.. If they call it beta isn't it supposed to be working? maybe they will fix Slashdot Beta and everyone will be happy again. Can you see this? I can't. What is wrong? Is this why they call it beta? I hope someone will be able to fix this because I am not happy it is not working. Maybe after the beta test is over it will work. It sure doesn't work now. I am getting even sadder.
It seems to work on the old site but the beta site is not ve

Mostly quantum mechanics. The fact that an electron can only exist at certain distances from the nucleus has to do with its wave properties. It's similar to how there is a minimum frequency that a guitar string can vibrate at due to its length, tension, and mass. Due to the forces and energies involved, there is a minimum distance that an electron can exist from a nucleus.

However, sometimes that minimum distance lies inside the nucleus. The element mercury (among others) can capture one of its own inner el

Car analogy time:I have gotten rid of vehicles that sucked less than the Slashdot beta. Seriously even that '85 Bronco II where everything was rusty, none of the body panels matched, and that had bad compression on the #5 cylinder sucked less than beta.slashdot.org.

Car analogy time:I have gotten rid of vehicles that sucked less than the Slashdot beta. Seriously even that '85 Bronco II where everything was rusty, none of the body panels matched, and that had bad compression on the #5 cylinder sucked less than beta.slashdot.org.

Car analogy time:I have gotten rid of vehicles that sucked less than the Slashdot beta. Seriously even that '85 Bronco II where everything was rusty, none of the body panels matched, and that had bad compression on the #5 cylinder sucked less than beta.slashdot.org.

They can but it requires making what one of my buddies called the "weak mighty bronco". Take a Bronco II and stuff in a Ford 460 with an appropriate manual transmission and some better axles and they they are great.

Nice off-topic comment If you don't like the Beta you don't have to use it.

reddit [reddit.com] This is a site which you think has a better layout than/. Beta how?

If you want to be critical of the new Beta fine but make that constructive criticism not what you are doing now which is not insightful especially when you criticise and basically insult Slashdot moderators who have generously marked you as that. Sure some the moderators may not be happy with the changes and even myself had problems with the Beta reply sys

"That raises the possibility that the shrinking readership would eventually meet the expanding Beta suckitude, which emerges with a sudden blast of "fuck beta" comments. That black would allow any insightful commentary trapped in the black hole to escape, solving the infamous -1 Insightful paradox."

I logged in, perused some of my old comments just for nostalgia and will be logging out for at least the remainder of the proposed boycott period.

I just wanted to say that it has been awesome being part of the Slashdot community. You guys are awesome. I have lost track of how much I have learned about different topics that I never would have learned were it not for participating in Slashdot discussions.

I hope to see you on the other side...with Beta existing only as a memory of an epic fail.

The idea is that quantum gravity stops the singularity from forming. It would still look like a black hole from the outside, for at least 10^100 years or so.

Quick elimination round:

Is it like a regular star? NoDoes this mean that we won't eventually end up with a universe full of black holes? No (but it would affect how these BH evaporate).Does this mean that there matter can actually escape from a black hole - yes, in their theoryand that there are no white holes? - not unless you view the end explosion a

Max Plank was the person who stated that energy might be quantized. That mean that energy cannot just appear in any quantity, but must exist in multiples of a specific quantity, E=hv, where h is Planks constant, and indicates that fundemental minimum energy. This was a desperate act to solve a possible problem and was really a change in direction for Planck. It was one of those mathematical things where one takes a logical step and conclusion

"The event horizon is not a special place, when you are close by, it looks just like any other close by place."

Of course in practical terms you can't stay alive near the event horizon due to the radiation from matter colliding in the accretion disk and the tidal effects.(unless you use a galactic center supermassive black hole thats not feeding.

Obtopic Beta : WTF is Dice anyway. I know there used to be a C compiler by that name back in the days when Fred Fish was collecting Free software for the Amigabut I